Ukrainian soldiers are assembling approximately 12 miles from the city of Donetsk after clashes with pro-Russian separatists throughout the eastern part of the country on Thursday.
The insurgents once again tried to seize control of the Donetsk airport, the site of a bloody battle in May that took place just one day after the presidential election.
Mashable's Christopher Miller, reporting from Donetsk, confirms seeing several armored vehicles and trucks carrying rebel fighters armed with heavy artillery and moving toward the airport.
In #Donetsk, smoke rising from the airport, and rebels on the move with artillery pic.twitter.com/YQGwzuL6qb— Christopher Miller (@ChristopherJM) July 10, 2014
"Shortly after, huge plumes of black smoke. Burst of gunfire. Sporadic explosions, likely from rocket-propelled grenades," Miller said.
The battle was brief, and there's no word yet on casualties.
There was also a fight in Karlivka, which is about 65 miles from Donetsk, on Thursday. Ukrainian forces claimed victory in that battle.
However, Miller noted that these small skirmishes hint that both sides may be preparing for a bigger fight on the horizon in eastern Ukraine.
Pavel Gubarev, the self-proclaimed governor of the Donetsk People's Republic, told Mashable on Wednesday that rebel forces would have "victory or death."
On the road in eastern Ukraine. Rebels blew up this bridge days ago to stop the advance of government forces. pic.twitter.com/dnVy7KoqCx— Christopher Miller (@ChristopherJM) July 10, 2014
However, divisions are starting to appear among the pro-Russia separatists fighting the Ukrainian government, especially as it becomes more and more evident that Russia isn't going to send in forces due to political pressure from the West.
"We would like to receive help in the form of Russian forces. But we are realists and understand that's impossible," Gubarev said during a news conference on Thursday
The head of one influential rebel battalion in eastern Ukraine said he will not submit to the command of the military leader of the separatist insurgency.
Vostok commander Alexander Khodakovsky also said Thursday he would not abandon the rebel-held city of Donetsk, even if ordered to do so. Though no such order has been issued, rebel troops did flee from their stronghold in Sloviansk last weekend.
In the past two weeks, Ukrainian government troops have halved the amount of territory held by the rebels. Now they are vowing a blockade of Donetsk.
Additional reporting by Christopher Miller in Ukraine and the Associated Press